Lock slider for zipper fastener



Jan. 30, 1962 o. J. HUELSTER LOCK SLIDER FOR ZIPPER FASTENER Filed June 10, 1959 INVENTOR OH'o J. Huelaier ORNEY can I United States Patent "cc 3,018,534 LOCK SLIDER FOR ZIPPER FASTENER Otto J. Huelster, Plymouth, Conn., assignor to Scovill Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filed June 10, 1959, Ser. No. 819,383 1 Claim. (Cl. 24-20514) My invention is an improvement in locking sliders for zipper fasteners and relates particularly to the type of lock sliders in which the fastener elements are pressed into locking engagement with an internal recess in the back wing of the slider by a cam or cams on the pull tab. The invention may be regarded as an improvement particularly on the patent to Osborne Firing and myself, No. 2,865,075 granted December 23, 1958.

In that patent, the advantage of elongated solid cams was recognized as important to withstand the stresses in a reverse pressing operation for zippers applied to such garments as trousers and dungarees. In all such sliders, where cams are employed to press the fastener elements into locking engagement with a recess in the back of the slider, the user was required to push the pull tab into locking position; otherwise, the slider could slip down allowing the fastener to open unintentionally. The wellknown pin-locking sliders have one advantage in this respect in that when the pull tab is released, it will normally fall into position where the pin will lever the pull tab into fully locked position upon any tendency of the slider to slip down, but of course, the pin-lock has many well-known disadvantages when used on trousers or dungarees including the liability to damage in a pressing operation.

My invention aims to provide an improved slider where the advantages of both the type exemplified by the above patent and also the pin-locking type, are obtained without the disadvantages of either one.

The manner in which this advantageous result is accomplished will be clear from the following description of one preferred embodiment of the invention illustrated in the accompanying drawings. In these drawings:

FIG. 1 is a perspective view of my improved lock slider;

FIG. 2 is a longitudinal section through the higher locking cam showing the slider in fully locked position;

FIG. 3 is a cross-section through the pivot axis of the pull tab taken along line 3-3 of FIG. 2 showing the slider fully locked;

FIG. 4 is a longitudinal section similar to FIG. 2 but showing the slider unlocked; and

FIG. 5 is a small scale view showing my improved slider in use on a zipper.

The slider body may be of any common form having a front wing 6 and a back wing 7 united by a neck 8 defining a Y-shaped channel for the passage of the two rows of zipper fastener elements 9 and 10. Projecting from the front wing is a lug, loop or bail 11 in which the pull tab 12 is pivotally connected by trunnions 13 and 14 on a relatively fixed axis, that is, it cannot shift an appreciable extent lengthwise of the slider. The earns 15 and 16 are laterally spaced, being located on opposite sides of the pu11-attaching lug 11. They are preferably of the elongated solid type shown in the above patent and they extend in the lengthwise direction on both sides of a perpendicular plane passing through the pull tab pivot axis.

The cam 15 is referred to as the higher cam although it is substantially higher only in that portion beyond the perpendicular plane through the pivot axis of the pull tab in the direction opposite the free end of the pull tab. This provides what might be called a nose 17, which as seen in FIG. 4, will enter the space between a pair of the fastener elements when the pull tab is allowed to 3,018,534 Patented Jan. 30, 1962 fall forward, which it would normally do after it is released. The corner 18 of one of the fastener elements will engage a point in the nose portion 17 of the cam 15 in the region beyond the perpendicular plane through the pull tab axis.

It will now be seen that any tendency for the slider to move down, such as would be caused by applying a tearing force as indicated by arrows in FIG. 5, will produce a leverage action on the pull tab swinging it down against the slider, thus avoiding the tendency for the fastener to slip open. When the pull tab is in fully locked position, both of the cams 15 and 16 will force the fastener elements into the recess 19 in the back wing of the slider where they will firmly lock against the shoulder 20 at the upper end of this recess. The front wing of the slider, of course, has an opening 21 to accommodate the cam 15 and a similar opening 22 to accommodate the cam 16.

The cam 16, in that region beyond the perpendicular plane passing through the pull tab axis extends in a wide curve as indicated at 23 so that it cannot lodge against one of the fastener elements when the nose 17 of the cam 16 is entering the space between two of the elements on the opposite side of the zipper. As seen in FIG. 3, the cam 16 cooperates with the cam 15 in pushing the fastener elements into the recess 19.

It will thus be seen that my improved slider has means for levering the pull tab into locked position, from an angled position which it normally assumes when the tab is released, and thus, does not demand that the user deliverately force the pull tab down. At the same time, the final locking is accomplished, not by a pin or the like hooking on to one of the fastener elements, but by the elements being pressed into a recess in the back wing of the slider.

What I claim:

An improved lock slider for zipper fasteners comprising front and back wings defining a Y-shaped channel, a pull tab pivotally attached to the front wing of the slider on a relatively fixed axis, a pair of laterally spaced elongated cams formed as a part of said pull tab and arranged in transverse alignment on opposite sides of the pivotal attachment of the pull tab, both cams extending in the lengthwise direction of the pull tab to each side of said axis of the tab, one cam having a high point at a greater distance from the pull tab axis than any portion of the other cam, said high point being in that portion adjacent the corner of the cam which lies beyond a plane perpendicular to the pull tab through said axis in the direction opposite the free end of the pull tab, said front wing having openings through which said cams pass into pressure engagement with fastener elements in the slider channel when the tab is moved down to locking position, and an internal recess in the back wing of the slider into which some of the fastener elements are forced by such pressure engagement to lock the slider in place, the high point of said one cam adapted to be engaged by a corner of one of the fastener elements when the pull tab is partly lowered to lever the tab into full locking position on application of a force on the fastener tending to move the slider downwardly, said other cam in that region beyond the aforesaid plane extending in a wide curve so that it does not lodge against one of the fastener elements on one side of the zipper when the high point of said one cam enters the space between two of the elements on the opposite side of the zipper.

References Cited in the file of this patent UNITED STATES PATENTS 

